As discussed in other threads, the 5088 replaces the 2577, and the 6088 replaces the 2588. The 7088 is a new model. Then the 7120 replaces the 7010, 8120 replaces the 8010, and the 9120s are also new models, though it looks like CIH is delaying their official launch.

Eliminated most controls on the armrest and went to a digital touch screen similar to the MX series tractors. The 6088 does not have the electric folding grain tank, only the 7088. Sieve area is a minimal difference from the 2588, though it is now electrically adjust from inside the cab. Feeder face is the larger size, however it's still the same feeder dimensions (new style heads, old size limitations). New air screens are sweet compared to the old ones. I believe the factory unload rate is around 2.8, though it can be made as fast or faster than the 8010 with a different sprocket. Nice looking machine. Runs great.